1. Field of the Invention
The present invention relates to a pneumatic tire, and particularly to a heavy duty pneumatic tire such as for trucks and buses in which uneven wear, especially a so-called heel and toe wear, is intended to be prevented. More specifically, the invention relates to a pneumatic tire suited for a pattern classified into an "all season pattern".
2. Description of the Related Art
The all season pattern is ordinarily excellent in its traction property on snow and wet roads due to the arrangement of blocks which are separatedly formed and arrayed by a plurality of main grooves extending zigzag in the circumference of the tread and linear transverse grooves transversing land portions each defined by the adjacent main grooves at a pitch corresponding to substantially a half of the zigzag pitch of the main grooves. But on the other hand, it is likely to produce an uneven wear pattern called heel and toe wear.
This problem has been heretofore dealt with exclusively through making coarser the arranging pitch of the linear transverse grooves to reduce the number of the transverse grooves arranged as compared with ordinary cases in which said pitch is substantially one half of the zigzag pitch, but a satisfactory effect could not be obtained. Further, although the groove width of the transverse grooves may be widened to make the negative area uniform in this case, the reduction in the traction performance is unavoidable.